feat: move version string to version.txt

- create version.txt to store the version number
- add function to read version from version.txt
- replace hardcoded version with dynamic retrieval

internal/metadata/version.go

@@ -1,6 +1,16 @@
 package metadata
 
-import "strings"
+import (
+	"os"
+	"strings"
+)
 
-const GoTomatoVersion = "0.1.1"                              // The GoTomato version
+func getVersion() string {
+	content, _ := os.ReadFile("version.txt")
+	version := strings.TrimSpace(string(content))
+
+	return version
+}
+
+var GoTomatoVersion = getVersion()                           // The GoTomato version
 var ProtocolVersion = strings.Split(GoTomatoVersion, ".")[0] // The protocol version

version.txt

@@ -0,0 +1 @@
+devel